package com.google.gwt.sample.stockwatcher.client;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.event.dom.client.ClickEvent;
import com.google.gwt.event.dom.client.ClickHandler;
import com.google.gwt.event.dom.client.KeyCodes;
import com.google.gwt.event.dom.client.KeyPressEvent;
import com.google.gwt.event.dom.client.KeyPressHandler;
import com.google.gwt.i18n.client.DateTimeFormat;
import com.google.gwt.i18n.client.DateTimeFormat.PredefinedFormat;
import com.google.gwt.i18n.client.NumberFormat;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.Window;
import com.google.gwt.user.client.rpc.AsyncCallback;
import com.google.gwt.user.client.ui.Anchor;
import com.google.gwt.user.client.ui.Button;
import com.google.gwt.user.client.ui.FlexTable;
import com.google.gwt.user.client.ui.HorizontalPanel;
import com.google.gwt.user.client.ui.Label;
import com.google.gwt.user.client.ui.RootPanel;
import com.google.gwt.user.client.ui.TextBox;
import com.google.gwt.user.client.ui.VerticalPanel;

/**
 * Entry point classes define <code>onModuleLoad()</code>.
 */
public class StockWatcher implements EntryPoint {

    private static final int REFRESH_INTERVAL = 5000; // ms

    private VerticalPanel mainPanel = new VerticalPanel();

    private FlexTable stocksFlexTable = new FlexTable();

    private HorizontalPanel addPanel = new HorizontalPanel();

    private TextBox newSymbolTextBox = new TextBox();

    private Button addStockButton = new Button("Add");

    private Label lastUpdatedLabel = new Label();

    private List<String> stocks = new ArrayList<String>();

    private StockPriceServiceAsync stockPriceService = GWT
            .create(StockPriceService.class);

    private Label errorMsgLabel = new Label();

    private LoginInfo loginInfo = null;

    private VerticalPanel loginPanel = new VerticalPanel();

    private Label loginLabel = new Label(
            "Please sign in to your Google Account to access the StockWatcher application.");

    private Anchor signInLink = new Anchor("Sign In");

    private Anchor signOutLink = new Anchor("Sign Out");

    private final StockServiceAsync stockService = GWT
            .create(StockService.class);

    /**
     * This is the entry point method.
     */
    public void onModuleLoad() {
        RootPanel.getBodyElement().addClassName("htmlBodyDefault");
        LoginServiceAsync loginService = GWT.create(LoginService.class);
        loginService.login(GWT.getHostPageBaseURL(),
                new AsyncCallback<LoginInfo>() {
                    public void onFailure(Throwable error) {
                        handleError(error);
                    }

                    public void onSuccess(LoginInfo result) {
                        loginInfo = result;
                        if (loginInfo.isLoggedIn()) {
                            loadStockWatcher();
                        } else {
                            loadLogin();
                        }
                    }
                });
    }

    private void loadLogin() {
        // Assemble login panel.
        signInLink.setHref(loginInfo.getLoginUrl());
        loginPanel.add(loginLabel);
        loginPanel.add(signInLink);
        RootPanel.get("stockList").add(loginPanel);
    }

    private void loadStockWatcher() {
        // Set up sign out hyperlink.
        signOutLink.setHref(loginInfo.getLogoutUrl());

        // Create table for stock data.
        stocksFlexTable.setText(0, 0, "Symbol");
        stocksFlexTable.setText(0, 1, "Price");
        stocksFlexTable.setText(0, 2, "Change");
        stocksFlexTable.setText(0, 3, "Remove");

        // Add styles to elements in the stock list table.
        stocksFlexTable.setCellPadding(6);
        stocksFlexTable.getRowFormatter().addStyleName(0, "watchListHeader");
        stocksFlexTable.addStyleName("watchList");
        stocksFlexTable.getCellFormatter().addStyleName(0, 1,
                "watchListNumericColumn");
        stocksFlexTable.getCellFormatter().addStyleName(0, 2,
                "watchListNumericColumn");
        stocksFlexTable.getCellFormatter().addStyleName(0, 3,
                "watchListRemoveColumn");

        loadStocks();

        // Assemble Add Stock panel.
        addPanel.add(newSymbolTextBox);
        addPanel.add(addStockButton);
        addPanel.addStyleName("addPanel");

        // Assemble Main panel.
        mainPanel.add(signOutLink);
        errorMsgLabel.setStyleName("errorMessage");
        errorMsgLabel.setVisible(false);

        mainPanel.add(errorMsgLabel);
        mainPanel.add(stocksFlexTable);
        mainPanel.add(addPanel);
        mainPanel.add(lastUpdatedLabel);

        // Associate the Main panel with the HTML host page.
        RootPanel.get("stockList").add(mainPanel);

        // Move cursor focus to the input box.
        newSymbolTextBox.setFocus(true);

        // Setup timer to refresh list automatically.
        Timer refreshTimer = new Timer() {
            @Override
            public void run() {
                refreshWatchList();
            }
        };
        refreshTimer.scheduleRepeating(REFRESH_INTERVAL);

        // Listen for mouse events on the Add button.
        addStockButton.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                addStock();
            }
        });

        // Listen for keyboard events in the input box.
        newSymbolTextBox.addKeyPressHandler(new KeyPressHandler() {
            @Override
            public void onKeyPress(KeyPressEvent event) {
                if (event.getCharCode() == KeyCodes.KEY_ENTER) {
                    addStock();
                }
            }
        });
    }

    private void loadStocks() {
        stockService.getStocks(new AsyncCallback<String[]>() {
            public void onFailure(Throwable error) {
                handleError(error);
            }

            public void onSuccess(String[] symbols) {
                displayStocks(symbols);
            }
        });
    }

    private void displayStocks(String[] symbols) {
        for (String symbol : symbols) {
            displayStock(symbol);
        }
    }

    /**
     * Generate random stock prices.
     */
    private void refreshWatchList() {
        // Initialize the service proxy.
        if (stockPriceService == null) {
            stockPriceService = GWT.create(StockPriceService.class);
        }

        // Setup the callback object.
        AsyncCallback<StockPrice[]> callback = new AsyncCallback<StockPrice[]>() {

            @Override
            public void onFailure(Throwable caught) {
                // If the stock code is in the list of delisted codes, display
                // an error message.
                String details = caught.getMessage();
                if (caught instanceof DelistedException) {
                    details = "Company '"
                            + ((DelistedException) caught).getSymbol()
                            + "' was delisted";
                }

                errorMsgLabel.setText("Error: " + details);
                errorMsgLabel.setVisible(true);
            }

            @Override
            public void onSuccess(StockPrice[] result) {
                updateTable(result);
            }
        };

        stockPriceService.getPrices(stocks.toArray(new String[0]), callback);
    }

    /**
     * Update the Price and Change fields all the rows in the stock table.
     * 
     * @param prices
     *            Stock data for all rows.
     */
    private void updateTable(StockPrice[] prices) {
        for (int i = 0; i < prices.length; i++) {
            updateTable(prices[i]);
        }

        // Display timestamp showing last refresh.
        lastUpdatedLabel.setText("Last update: "
                + DateTimeFormat.getFormat(PredefinedFormat.DATE_TIME_MEDIUM)
                        .format(new Date()));

        // Clear any errors.
        errorMsgLabel.setVisible(false);
    }

    /**
     * Update a single row in the stock table.
     * 
     * @param price
     *            Stock data for a single row.
     */
    private void updateTable(StockPrice price) {
        // Make sure the stock is still in the stock table.
        if (!stocks.contains(price.getSymbol())) {
            return;
        }

        int row = stocks.indexOf(price.getSymbol()) + 1;

        // Format the data in the Price and Change fields.
        String priceText = NumberFormat.getFormat("#,##0.00").format(
                price.getPrice());
        NumberFormat changeFormat = NumberFormat
                .getFormat("+#,##0.00;-#,##0.00");
        String changeText = changeFormat.format(price.getChange());
        String changePercentText = changeFormat
                .format(price.getChangePercent());

        // Populate the Price and Change fields with new data.
        stocksFlexTable.setText(row, 1, priceText);
        // stocksFlexTable.setText(row, 2, changeText + " (" + changePercentText
        // + "%)");
        Label changeWidget = (Label) stocksFlexTable.getWidget(row, 2);
        changeWidget.setText(changeText + " (" + changePercentText + "%)");

        // Change the color of text in the Change field based on its value.
        String changeStyleName = "noChange";
        if (price.getChangePercent() < -0.1f) {
            changeStyleName = "negativeChange";
        } else if (price.getChangePercent() > 0.1f) {
            changeStyleName = "positiveChange";
        }

        changeWidget.setStyleName(changeStyleName);
    }

    /**
     * Add stock to FlexTable. Executed when the user clicks the addStockButton
     * or presses enter in the newSymbolTextBox.
     */
    private void addStock() {
        final String symbol = newSymbolTextBox.getText().toUpperCase().trim();
        newSymbolTextBox.setFocus(true);

        /*
         * Stock code must be between 1 and 10 chars that are numbers, letters,
         * or dots.
         */
        if (!symbol.matches("^[0-9A-Z\\.]{1,10}$")) {
            Window.alert("'" + symbol + "' is not a valid symbol.");
            newSymbolTextBox.selectAll();
            return;
        }

        newSymbolTextBox.setText("");

        /*
         * Add the stock to the table. Don't add the stock if it's already in
         * the table.
         */
        if (!stocks.contains(symbol)) {
            addStock(symbol);
        }
    }

    private void addStock(final String symbol) {
        stockService.addStock(symbol, new AsyncCallback<Void>() {
            public void onFailure(Throwable error) {
                handleError(error);
            }

            public void onSuccess(Void ignore) {
                displayStock(symbol);
            }
        });
    }

    private void displayStock(final String symbol) {
        stocks.add(symbol);
        int row = stocksFlexTable.getRowCount();
        stocksFlexTable.setText(row, 0, symbol);
        stocksFlexTable.setWidget(row, 2, new Label());

        stocksFlexTable.getCellFormatter().addStyleName(row, 1,
                "watchListNumericColumn");
        stocksFlexTable.getCellFormatter().addStyleName(row, 2,
                "watchListNumericColumn");
        stocksFlexTable.getCellFormatter().addStyleName(row, 3,
                "watchListRemoveColumn");

        /*
         * Add a button to remove this stock from the table.
         */
        Button removeStockButton = new Button("x");
        removeStockButton.addStyleDependentName("remove");
        removeStockButton.addClickHandler(new ClickHandler() {
            @Override
            public void onClick(ClickEvent event) {
                removeStock(symbol);
            }
        });
        stocksFlexTable.setWidget(row, 3, removeStockButton);

        // Get the stock price.
        refreshWatchList();
    }

    private void removeStock(final String symbol) {
        stockService.removeStock(symbol, new AsyncCallback<Void>() {
            public void onFailure(Throwable error) {
                handleError(error);
            }

            public void onSuccess(Void ignore) {
                undisplayStock(symbol);
            }
        });
    }

    private void undisplayStock(String symbol) {
        int removedIndex = stocks.indexOf(symbol);
        stocks.remove(removedIndex);
        stocksFlexTable.removeRow(removedIndex + 1);
    }

    private void handleError(Throwable error) {
        Window.alert(error.getMessage());
        if (error instanceof NotLoggedInException) {
            Window.Location.replace(loginInfo.getLogoutUrl());
        }
    }

}
